Sound apparatus



April 2, 1940. H. E. HOLLIDAY 2,195,651

SOUND APPARATUS Filed Feb. 17, 19:58

r 9 %BS Patented Apr. 2, 1940 PATENT OFFICE sown: APPARATUS" Herbert E.'Holliday, Detroit, -Mich.,- assignor to General Motors Corporation,Detroit, Mich a corporation Delaware Application February 17,1928,Serial-No. 190,986

2 Claims.

This invention relates to sound apparatus and more particularly toapparatus for translating electrical pulsations into sound waves.-

It is often desirable in mounting a loud speaker 45 unit in a cabinet orat some other location within an inclosure, to vary the characteristicsof the enclosing chamber to better cooperate with the acousticcharacteristics of the surroundings to give a well balanced resultantsound wave. Particularly with regard to the mounting of the separatespeaker units as employed in automotive sets is it desirable to havesuch a unit. This is true because the acoustic properties of theinterior of the different cars vary a great deal even in the same modelof one particular make and widely between makes. This is due to thedifferent cubic content of the bodies; the location of the panel uponwhich the speaker is mounted; the type of upholstering; position of thesets, etc.

It is therefore an object of my invention to provide a housing for theloud speaker which may be adjusted after the speaker has beenpermanently mounted to cooperate with the acoustic 25 enclosure withinwhich the whole is mounted.

It is a further object of my invention to provide a housing which may bemanually and simply adjusted and which will not raise the costappreciably over that of the usual housing.

With these and other objects in view my invention will be bestunderstood by reference to the following specification and claims, thecontent of which is illustrated in the accompanying drawing, in which:

Figure 1 is a side elevation, parts being broken away and shown insection, of a speaker mounted within an automotive vehicle.

Figure 2 is a front view of the speaker.

Figure 3 is an enlarged side view of the speaker mounted on the panel,parts being broken away and shown in section.

Figure 4 is a side elevation similar to Figure 3 of a modified form ofmy invention.

As is customary in the present cars, the sep- 45 arate speaker such asthat shown generally at 2, is usually mounted upon the dash 4 of a car 6and connected by a cable to a radio receiving set 8 located behind theinstrument panel. The particular construction in this case consists of acircular backing disk Ill to which is rigidly secured the loud speakerunit I! which carries the vibrating diaphragm l4 and a metallicenclosing structure H3 at the opposite end. The member I! has protrudingtherefrom a threaded bolt l8 which proceeds through a spacing member- 20"between the member l2 and the plate i0 andthere is threaded thereon anut 22 to securethis assembly together.

To the rear face of the disk I0 is applied a plurality' of washers, theinner one having a center cavity such as shown at 26 to fit over the nut22. The bolt I8 then proceeds through the disc 4 and there is applied tothe opposite face a suitable washer and nut 28 to clamp the assembly tothe dash or supporting panel.

Secured at certain spaced intervals around the periphery of the disk IDare angled slotted brackets 30 which have a bent-over ear 32 secured tothe plate by machine screws 34. The opposite end of the bracket extendsto a greater distance from the disk l0 and has a leg portion 36, thelower end of which is bent at right angles thereto and also secured to,the disk ill by a screw such as 34. This provides a partially circulartrack 38 at spaced portions of the periphery, there being in this casefour of these members secured to the backing disk l0.

Mounted over the whole assembly on the forward face of the disk l0 thereis a large drumshaped member 40, the forward face of which has a largeopening 42 therein coincident with the forward face of the loud speakerand in this opening there is provided a cloth grille 44 through whichthe sound waves may pass. Adjacent the inner surface of this openingthere is an annular soft washer 46 which at certain positions of thedrum is adapted to seal with the forward face of the edge of the memberl6 supporting the diaphragm.

In the surface of the drum at spaced points around the inner peripherythere are a series of openings 48 through which bolts 50 are insertedhaving threaded to their inner surfaces a washer 52 and nut 54, thelatter not being tightened to too great a degree and the washer 52having a certain resiliency. These bolts 50 proceed through a portion ofthe slots 38 in the members 30 so that asthe drum 4!] is rotated theywill cause. the drum to move axially of the speaker mounting. When thedrum is rotated in a clockwise direction, looking at the speaker fromthe right-hand side of Figure 3, the bolts will cause the drum to bedrawn in and the drum to contact the plate I0 and the annular washer 46around the edges of the diaphragm. Thus it will be seen that achange inthe tonal qualities of the speaker may be had by merely manuallytwisting this outer housing and after the speaker has been mounted inthe car the operator may tune in a desired station and then set thehousing at what he deems to be the point of maximum efliciency inreceiving.

The modification shown in Figure 4 is substantially the same except thatin this instance a cross member 56 supported on the means holding thediaphragm is provided with a central" threaded opening 58 and thehousing 40' has supported across its center opening a similar supportingbracket 60. This latter bracket has firmly secured to its center ascrew-threaded member 62 which may be threaded into the Otherwise themember 58 in the bracket 56. speaker and speaker mounting are supportedin exactly the same manner on the disk I0 and of course in this instanceas the housing 40' is rotated it will be moved axially of the speaker toadjust or change the loading of the back face of the speaker by changingthe rear chamber and also by varying the acoustic chamber in front ofthe speaker.

I claim:

1. In a sound device assembly, a mounting plate, a sound devicecomprising a vibratile diaphragm mounted on said plate and having anoutwardly extending peripheral portion, supporting brackets on saidplate arranged concentrically of the axis of said sound device andhaving slots inclined to the plane of said plate, a substantiallycylindrical housing surrounding and spaced from the peripheral portionof said sound device and having an opening in alignment therewith, asealing member secured to said housing adjacent and around the edge ofsaid opening, projections on said housing engaging the slots in saidbrackets for rotatably supporting the housing relative to said plate,whereby rotation of the housing relative to said plate will cause axialmovement of the housing between a position in which the sealing membercontacts the sound device and a widely open position, and the airloading on said vibrating diaphragm may be varied.

2. In a sound device assembly, a mounting plate, a sound device havingan outwardly extending peripheral portion mounted on said plate,supporting brackets on said plate arranged concentrically of the axis ofsaid sound device and having slots inclined to the plane of said plate,a housing surrounding said sound device and spaced from said peripheralportion, projections on said housing slidably engaging the slots in saidbrackets for rotatably supporting the housing relative to said plate tocause axial movement of the housing relative to said plate on rotationof the housing.

' HERBERT E. HOLLIDAY.

